CHAPTER XXXm 



CLASS 2 SUCTORIA BUTSCHLI 



THE SUCTORIA, which are also called the Acineta, Acinetaria, 

 Tentaculifera, etc., do not possess any cilia or any other 

 cell-organs of locomotion in the mature stage. The cilia are 

 present only on young individuals which are capable of free- 

 swimming, and are lost with the development of a stalk or an 

 attaching disc, and of tentacles. Therefore, an adult suctorian 

 is incapable of active movement. The body is covered with a 

 pellicle and occasionally possesses a lorica. There is no cyto- 

 stome, and the food-capturing is carried on exclusively by the 

 tentacles. Tentacles are of two kinds. One is suctorial in func- 

 tion and bears a rounded knob on the extremity. It is found in 

 many genera. The other kind of tentacle is for piercing and is, 

 more or less, sharply pointed, as in Ephelota. These tentacles 

 may be confined to limited areas or may be formed from the 

 entire body surface. The prey is usually small ciliates. Nutri- 

 tion is holozoic. 



The body of a suctorian may be spherical, elliptical, den- 

 dritic, etc. Asexual reproduction is by binary fission or budding. 

 The buds which are formed by either exogenous or endogenous 

 gemmation are ciliated, and swim around actively after leav- 

 ing the parent individual. Finally becoming attached to a 

 suitable object, they metamorphose into adult forms. Sexual 

 reproduction is through copulation. The Suctoria live attached 

 to animals, plants, or non-living matter submerged in fresh or 

 salt water. 



According to Collin, the Suctoria are here divided into eight 

 families as follows: 



Adult without cilia 



With Suctorial tentacles only 

 Body irregular or branching 

 Without proboscis or special arms. Body form highly variable; 



often with stolon ; but usually without a stalk 



Family 1 Dendrosomidae 



[399] 



